Vol 52, No 14 (2016)

A procedure for sensitive determination of rocket kerosene in water is described; it includes the dispersive liquid–liquid microextraction of analytes followed by their separation and determination by gas chromatography mass spectrometry in the mode of chromatogram registration against selected ions (m/z: 67, 81, 85, 95, 136, 137, 174, 183, and 193). The effect of the nature and volume of disperser and extraction solvents, salt additives, and the extraction duration on the efficiency of extraction of analytes is studied. The detectable concentration range is 0.005–0.05 mg/L. The detection limits (S/N = 3) of kerosene RG-1 and T-1 are 0.0015 and 0.0022 mg/L, respectively. The repeatability of the measurement results for the above range varies from 16 to 9% (n = 3); the intermediate precision varies from 20 to 12% (n = 5).

A review of the published works on the use of different methods of analysis for studying anthropogenic pollution of environmental objects with platinum group metals (PGMs) for 2011–2013 is presented. The results of the recent studies on the content of PGMs in environmental objects of big cities are provided.

The energies of chemisorption of As, Se, Pb, and Cd atoms by the metal surface of iron are calculated by the quantum chemistry method. The possibility of analytical application of an iron-containing chemical modifier (CM) on the basis of activated carbon for ETAAS determination of volatile elements is suggested. By the methods of thermodynamic modeling, thermal analysis, and ETAAS, the preparation procedure of iron-containing CM is justified on the basis of activated carbon, which ensures the formation of the metallic phase Fe⁰ and the course of low-temperature thermal stabilization of analytes. Using the developed chemical modifier, the contents of As, Cd, and Pb are determined in the suspensions of the standard sample of seaweeds. The results are in satisfactory agreement with the certified values.

The techniques of atomic emission spectrometry with inductively coupled plasma (ICP-AES) for quantitative determination impurities in silicon, germanium, and their dioxides are developed. Analytical lines for silicon-matrix (29 trace elements) and germanium-matrix (42 trace elements) are selected. Matrix interferences caused by the presence of silicon and germanium in the solutions are studied. The optimal concentrations of matrix are determined. LODs for trace elements are in the range from n × 10^–7 to n × 10^–5 wt %; RSD < 20%. The accuracy of the results is confirmed by the method of “introduced–found.” The developed techniques are express, simple, and can determine a broad range of trace elements.

Physicochemical properties inherent in the solid component of welding aerosols (SCWA) are characterized. The features of SCWA sampling are considered. Methods are indicated which are most commonly used for the analysis of SCWA in Russian and foreign analytical practice. Destructive and nondestructive methods of SCWA analysis are compared, and their advantages and disadvantages are noted. By particular examples, it is shown that because of the complexity of phase and chemical composition of SCWA samples, rather frequently, one observes a loss of monitored elements in the course of the decomposition of exposed filters. Techniques for making synthetic calibration samples are considered for both classes of methods. In the case of using the X-ray fluorescence method, it is difficult to prepare calibration samples adequate to real SCWA samples collected on a filter. The comparative variant of neutron activation analysis involves synthetic mixtures for the calculation of the content of analytes containing one or two components. Metrological characteristics are presented for SCWA analysis techniques.

The technology of gold extraction to lead from its mixture with the sample powder during lowtemperature alkaline fusion is developed. The optimal ratios of masses for the sample, lead, and alkali, as well as heating conditions, temperature, and fusion duration, are determined for satisfactory gold recovery. A low temperature of fusion makes it possible to lighten the structure of furnaces, to decrease energy consumption, and to shorten the duration of the entire cycle from the beginning of fusion until the next set of crucibles is loaded. Using the modular approach, a furnace can be assembled in a small area for the simultaneous fusion of a great number of samples. The results of determining gold by the X-ray fluorescence method obtained by using the proposed concentration technology satisfy the regulatory requirements with respect to accuracy.

The analytical potential of direct arc atomic emission detection of impurities in rare earth oxides (Y₂O₃, Cd₂O₃, and Nd₂O₃) on a Grand-Extra high-resolution spectrometer (VMK-Optoelektronika, Russia) is assessed. The conditions of analysis and spectrometer parameters are optimized. The detection threshold and lower limits for the content of a number of rare earth elements (Nd, Eu, Dy, Ho, Gd, Er, Tm, Yb, and Y) in these oxides are determined. The procedure for direct arc atomic emission analysis of yttrium, gadolinium, and neodymium oxides to detect rare earth impurities within the range of 0.001–0.1 wt % is elaborated; the procedure is characterized by improved metrological parameters compared to the standard method.